"It's a pretty quiet neighborhood never really thought anything was going on across the street," said Ben Sides, who lives on Leland Avenue.

Des Moines police said narcotics officers located an individual who was making purchases of very high-grade marijuana from a residence at 1012 Leland Ave. in Des Moines.

Police said one of the people arrested at the address was seen making drug transactions.

"I noticed that there seemed to be a good amount of traffic going in and out, but I never really thought too much about it, or I guess my mind didn't jump to the idea of some sort of drug operation going on," said Sides.

Police said investigators were able to obtain a search warrant for the Leland address. Once inside, narcotics officers located and confiscated approximately 150 marijuana plants that would be able to yield an estimated 40 pounds of marijuana.

The estimated street value of this is in excess of $100,000, according to police.

Narcotics detectives told KCCI-TV that this was one of the most significant marijuana growing operations that they've see in a long time.

In addition to the plants, police said they also confiscated sophisticated growing equipment. Items seized included an assortment of grow lights, tents, chemical sprayers, a water supply/filtration system, timers and devices used to infuse carbon dioxide into the plants.

"They found what's called a hydroponic grow operation," said Sgt. Jason Halifax, Des Moines police spokesman. "A very elaborate set up -- water filtration systems, times, grow lights, tents for the plants."

The equipment is estimated to be worth $40,000-50,000.

This type of operation typically produces a higher-quality product, according to police.

"If you look at the size of the operation and the amount of equipment that was there you can really easily guess at least months," said Halifax.

Also seized was a smaller quantity of methamphetamine, powdered cocaine and 2 loaded handguns.